It has been disclosed that certain polyesters may be formed which exhibit melt anisotropy. See, for instance, (a) Polyester X7G-A Self Reinforced Thermoplastic, by W. J. Jackson Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics/Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1 to 4, (b) Belgian Pat. Nos. 838,935 and 828,936, (c) Dutch Pat. No. 7505551, (d) West German Pat. Nos. 2520819, 2520820, 2722120, 2834535, 2834536, and 2834537, (e) Japanese Pat. Nos. 43-223; 2132-116; 3017-692; and 3021-293, (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,118,372; 4,130,545; 4,130,702; 4,156,070; 4,159,365; 4,161,470; 4,169,933; and 4,181,792; and (g) U.K. Application No. 2,002,404. See also commonly assigned U.S. Ser. Nos. 10,392, filed Feb. 8, 1979 now U.S. Pat. No. 4,238,599, issued Dec. 9, 1980; 10,393, filed Feb. 8, 1979 (now U.S. Pat. No. 4,238,598); and 32,086, filed Apr. 23, 1979 now U.S. Pat. No. 4,219,461, issued Aug. 26, 1980.
Additionally, in commonly assigned U.S. Pat. No. 4,184,996 is disclosed a polyester which consists essentially of p-oxybenzoyl, 2,6-dioxynaphthalene, and terephthaloyl recurring units. In commonly assigned U.S. application Ser. No. 54,049, filed July 2, 1979 now U.S. Pat. No. 4,256,624, issued Mar. 17, 1981, is disclosed a polyester which consists essentially of 6-oxy-2-naphthoyl, dioxyaryl, and dicarboxyaryl recurring units. Schaefgen, U.S. Pat. No. 4,118,372, broadly discloses polyesters which exhibit an anisotropic melt phase and which consist essentially of recurring units derived from diacids, diols, and hydroxy acids. The inclusion of a 1,4-dicarboxycyclohexane moiety is disclosed, for example, at column 2, line 5 and in several of the Examples. Furthermore, R.sub.1, R.sub.2, and R.sub.3 in the formulas of U.S. Pat. No. 4,118,372 may be, as defined in Columns 1 and 2, "radicals selected from the group of (1) single and fused 6-membered aromatic carbocyclic ring systems wherein the chain extending bonds of the ring system if attached to the same ring are positioned 1,4- to each other, and if attached to different rings, are in positions parallel and oppositely directed, . . . ." Two-ring systems are illustrated at Column 2. However, a polyester which incorporates a moiety derived from 6-hydroxy-2-naphthoic acid is not identified anywhere in the patent. Moreover, it has not previously been disclosed to provide a polyester resulting from the unique combination of recurring units derived from 6-hydroxy-2-naphthoic acid and trans-1,4-cyclohexanedicarboxylic acid, together with recurring units derived from an aromatic diol.
Therefore, it is an object of the present invention to provide an improved polyester which is suited for the formation of quality molded articles, melt extruded fibers, and melt extruded films.
It is also an object of the present invention to provide an improved melt processable polyester capable of forming an anisotropic melt phase at a temperature below approximately 350.degree. C., and preferably below approximately 320.degree. C.
It is also an object of the present invention to provide an improved polyester which forms a highly tractable melt phase.
It is also an object of the present invention to provide an improved polyester which forms an anisotropic melt phase at a temperature well below its decomposition temperature and which may form quality fibers, films, and molded articles.
It is also an object of the present invention to provide an improved polyester which is capable of forming molded articles exhibiting high impact strength.
These and other objects, as well as the scope, nature, and utilization of the present invention, will be apparent to those skilled in the art from the following detailed description.